The present invention relates to an organotin stabilizer mixture, suitable for use in rigid vinyl polymer formulations, which combines several positive and beneficial properties into a single stabilizer composition. The stabilizer formulation provides improved early color, lubricity, and weatherability.
A wide variety of organotin containing stabilizer formulations are known to persons of ordinary skill in the art for use in a variety of polymer compositions including rigid vinyl formulations. Some examples of organotin formulations which are deemed generally relevant to the present invention include the following:
O. S. Kauder U.S. Pat. No. 3,632,538 shows the use of an organotin alpha- or beta-mercapto carboxylic acid ester and an organotin sulfide in PVC resin formulations.
R. D. Dworkin et al U.S. Pat. No. 4,104,292 discloses organotin derivatives of mercaptoalcohol esters.
J. M. Bohen et al. U.S. Pat. No. 4,115,352 illustrates mixtures of alkali and alkaline earth metal salts of mercaptans or mercapto acids with specified sulfur containing organotin or antimony compounds as heat stabilizers for halogenated resins.
L. R. Brecker et al. U.S. Pat. No. 4,255,320 illustrates stabilizer mixtures comprising a monoalkyl 2-acyloxyethylmercaptide and/or a dialkyltin 2-acyloxyethylmercaptide in admixture with an alkyltin sulfide.
In general, two types of organotin stabilizers are in common usage in vinyl chloride polymer formulations: the mixed metal soap type; and tin stabilizers based on mixtures of monoalkyltin and dialkyltin stabilizer compounds. The monoalkyltin compounds generally give good color, whereas the dialkyltin compounds give good long term stability. The present invention relates to a monoalkyltin stabilizer mixture which is preferably adapted to be blended, in various desired ratios, with conventional dialkyltin stabilizer(s), such as the preferred dibutyltin stabilizer compound(s), for use in vinyl chloride polymer formulations.